The present invention relates generally to an electrode structure of a liquid crystal display, and more particularly to an electrode structure of a wide viewing angle liquid crystal display.
A large number of liquid crystal display (LCD) panels have recently been employed as display devices in electronic products. The technologies of wide viewing angle liquid crystal displays have been disclosed very often in recent years. In a Taiwan patent application No. 88108187 entitled xe2x80x9cElectrode Structure of A Wide Viewing Angle Liquid Crystal Displayxe2x80x9d, an electrode structure for providing wide viewing angle is disclosed. The electrode structure comprises an upper electrode layer having multiple comb-shaped and parallel conductors on a glass substrate, a lower electrode layer having a TN-type conductor and a layer of non-conductive insulator formed between the upper and lower electrode layers.
In the embodiment of the Taiwan patent application, the pixel electrodes in the upper layer of the electrode structure has a comb-shaped structure while the common electrode in the lower layer has a plate-shaped structure. A layer of negative-type liquid crystal is used to fill the space between the upper and lower glass substrates of the LCD. The two electrode layers are fabricated on the lower glass substrate.
The drawback of the electrode structure disclosed in the Taiwan patent application is that the liquid crystal driven by an electric voltage rotates toward one direction. Therefore, the effect of color dispersion at different viewing angle limits the viewing angle of the LCD and degrades the quality of the display.
The present invention has been made to overcome the above-mentioned drawback of the electrode structure in the prior art. The primary object of the invention is to provide an electrode structure for a wide viewing angle liquid crystal display. The electrode structure has upper and lower electrode layers. The pixel electrode in the upper layer has a herringbone-shaped structure while the common electrode in the lower layer has a plate-shaped structure.
The liquid crystal display has two separated glass substrates between which liquid crystals are filled. Multiple scan signal lines, multiple data signal lines, multiple switching elements, and a layer of common electrodes are fabricated on the surface of the lower glass substrate. The scan signal lines are perpendicular to the data signal lines in order to form a pixel matrix. A passivation layer made of a transparent non-conductive insulator is formed between the layer of pixel electrodes and the layer of common electrodes.
The herringbone-shaped structure of the pixel electrodes allows the liquid crystal molecules to rotate in two directions, clockwise and counterclockwise. The color dispersion caused by a wide viewing angle is thus compensated for. The herringbone-shaped structure also helps to maintain the brightness of pixels.
The foregoing and other objects, features, aspects and advantages of the present invention will become better understood from a careful reading of a detailed description provided herein below with appropriate reference to the accompanying drawings.